Histopathological and ultra-structural investigation of the damaging effects of hypoinsulinemia, hyper glycaemia and oxidative stress caused by parenteral nutrition combined with fasting on the small intestine of rabbits.

BACKGROUND AND STUDY AIMS: Parenteral nutrition (PN) is a life-saving practice when the use of the gastrointestinal tract is not appropriate. Despite its great benefits, however, PN may cause several complications. In this study, we conducted histopathological and ultra-structural examinations of the effect of PN combined with starvation on the small intestines of rabbits.

MATERIALS AND

METHODS

Rabbits were divided into four groups. A fasting + PN group was left completely unfed and received all its daily required energy by PN through an intravenous central catheter. An oral feeding + PN group received half the necessary daily calories by oral feeding and the other half through PN. A semi-starvation group received only half the necessary daily calories by oral feeding and no PN. The fourth group, serving as a control, was supplied with its entire daily energy requirements through oral feeding. After 10 days, the rabbits were euthanized. Blood and small intestine tissue samples were collected from all groups. Blood samples were biochemically analysed, and tissue samples were examined by light and transmission electron microscopy.

RESULTS

The fasting + PN group exhibited lower insulin levels, higher glucose levels, and increased systemic oxidative stress than the other groups. Ultra-structural and histopathological examinations revealed a significant increase in apoptotic activity in this group's small intestines and a significant decrease in villus length and crypt depth. Severe damage to the intracellular organelles and nuclei of enterocytes was also observed.

CONCLUSION

PN combined with starvation appears to cause apoptosis in the small intestine due to oxidative stress and hyperglycaemia with hypoinsulinemia, with destructive effects on small intestine tissue. Adding enteral nutrition to PN may reduce these destructive effects.